WASHINGTON, April 21 (Reuters) - African finance ministerstold their rich nation counterparts at weekend meetings of theInternational Monetary Fund and World Bank to work harder andfaster to kick-start their economies to avoid a prolonged slumpthat could undermine strong growth in the developing world.

"We are concerned," Nigerian Finance Minister NgoziOkonjo-Iweala said at the meetings of global finance leaders.

"If we continue to see slow growth in the euro zone, whichprovides a large market for many African countries, and iscoupled with a slowdown in emerging economies, then we willbecome more vulnerable," Okonjo-Iweala told a news conference ofAfrican finance ministers. "We need to insist that our partnersin other parts of the world work harder and faster."

Despite a global economic slowdown in 2012, most Africaneconomies grew at close to 6 percent buoyed by strong internaldemand and higher commodity prices. Strong and better managedeconomies have also attracted investors' attention, with netcapital flows to the region reaching a record $54.5 billion lastyear, an increase of 3.3 percent from 2011.

But figures released by the World Bank last week showed thatmost of the world's poor are now concentrated in Africa despiteincreased economic growth.

African economies are also hobbled by poor infrastructure,high unemployment and growing inequality. The region alsoremains vulnerable to droughts and floods, and pockets ofinstability.

Okonjo-Iweala said the region was concerned with how centralbanks in advanced economies planned to exit from years of easymonetary policy, which has led to a surge in investment capitalin emerging and developing countries.

Aggressive stimulus from central banks in the United States,Britain, the euro zone and now Japan has so far failed to sparka reliable recovery, and questions are already being raised overhow much more monetary policy can - or should - do.

Okonjo-Iweala emphasized it will be important for centralbanks to signal early on when they intend to change course.

"The signaling should be given ahead so we can prepare oureconomies for what the consequences might be, is importantbecause we don't want to precipitate a situation in which moneysuddenly flows out of the countries," she said.

"But also, for us, we should be looking at our owninstruments that we can apply should we have problems withvolatility that arises out of some portfolio flows that mighthave come in," she added.

Cameroon's finance minister, Alamine Ousmane Mey, saidAfrican economies had built up more resilience to withstandeconomic downturns. Increased trade with the BRICS emergingeconomies of Brazil, Russia, India, China and South Africa hasalso helped, he added.

"The BRICS countries which allow us to diversify our tradeand rebalance a situation where growth in advanced economies hasslowed down," he said.

LASTING RECOVERY

While Africa has witnessed booms before, many questionwhether this time Africa's growth takeoff will stick. New IMF research finds that it is likely to stay on course if countriesmaintain the strong economic policies of the past 10 years.

Antoinette Sayeh, the IMF's director for Africa, believesthe region has turned a corner.

"We certainly are optimistic that growth will continue to berobust and have an uptick as global growth itself recovers,"Sayeh told Reuters. "We think the conditions that underpin thisrobust growth in the past are still very much there, that isgood macroeconomic management in many countries, good commodityprices, strong investment both domestic and foreign investmentin a number of countries."

Last week, the IMF forecast that Africa will grow at 5.6percent this year and picking up to 6.1 percent in 2014, withIvory Coast and Mozambique growing at the fastest clip.

Sayeh said a sustained stagnation in Europe and sharpdownturn in investment by large emerging economies posed thebiggest risks to the region. "Could it derail growth? Ourassessment is that, absent a truly dramatic shock to the globaleconomy, probably not because it is not just externallypropelled growth, it is also domestic. That is the difference,"she added.

Sayeh, a former Liberian finance minister, said countriesshould prioritize spending and those that could afford it shouldrebuild their fiscal safety nets.

Turning to Kenya, east Africa's largest economy, Sayeh saidthe economic outlook was "bright" following a peaceful vote onMarch 4 that elected Uhuru Kenyatta, 51, as president. Electionsfive years ago were marred by violence, leaving more than 1,200dead and hammering the economy.

"Now with a clarified political scene, it is an opportunityto see Kenya's potential takeoff. That requires a sustainedcommitment and implementation of reform as we think governmentintends to pursue," said Sayeh. "There is a lot of interest onthe part of investors in Kenya and sustaining the reforms willbe important."